Intramuscular Lipid Research Articles

Palmitic acid uptake by the rat soleus muscle in vitro

Abstract: The rate of fatty acid uptake, oxidation, and deposition in skeletal muscles in relation to total and unbound to albumin fatty acids concentration in the medium were investigated in the incubated rat soleus muscle. An immunohistochemical technique was applied to demonstrate whether the albumin-bound fatty acid complex from the medium penetrates well within all areas of the muscle strips. It was found that the percentage of incorporation of palmitic acid into intramuscular lipids was fairly constant, independently of the fatty acid concentration in the medium, and amounted to 63-72% for triacylglycerols, 7-12% for diacylglycerols-monoacylglycerols, and 19-26% for phospholipids. Both palmitic acid incorporation into the muscle triacylglycerol stores and its oxidation to CO2 closely correlated with an increase in both total and unbound to albumin fatty acid concentrations in the incubation medium. Under conditions of increased total but constant unbound to albumin palmitic acid concentrations, the incorporation of palmitic acid into triacylglycerols and its oxidation to CO2 were also increased, but to a lower extent. This supports the hypothesis that the cellular fatty acid metabolism depends not only on the availability of fatty acids unbound to albumin, but also on the availability of fatty acids complexed to albumin.

Study of the branched hydrocarbon fraction of intramuscular lipids from Iberian fresh ham

Branched hydrocarbons from the unsaponifiable lipid fraction of the Biceps femoris muscle of Iberian pigs were analyzed. Fifty-five Iberian pigs were distributed to seven groups according to management system ( short Montanera and long Montanera, i.e. fed on acorn and pasture for 55 and 75 days prior to slaughter, respectively, and Pienso, fed on a concentrate diet), and genetic type. A branched hydrocarbon, neophytadiene, was identified only in samples from the pigs fed on the extensive system, with higher levels being found in pigs from the long Montanera group, than in those from the short Montanera group; this compound was not found in the Pienso group. Genotype did not affect the level of branched hydrocarbons found.

Lipids in monogastric animal meat.

Meat from monogastric animals, essentially pigs and poultry, is from afar the most consumed of all meats. Meat products from every species have their own characteristics. For a long time, pig meat has been presented as a fatty meat because of the importance of subcutaneous adipose tissue. Actually, when the visible fat is separated, this meat is rather poor in lipids: pieces eaten as fresh meat and without transformation, such as roasts, contain less then 2% total lipids. Poultry meat has always had a reputation of leanness because of its low content in intramuscular lipids. In addition, adipose tissues, localised in the abdominal cavity, are easily separable. The progress in genetics and a better knowledge of dietary needs has allowed to improve growth performances, to increase muscle weight and, in the pig, to strongly decrease carcass adiposity. However, strong contradictions appear between transformers and nutritionists, especially concerning the pig: the former wish to have meat with adipose tissues containing a high percentage of saturated fatty acids and the latter wish meat with more unsaturated fatty acids. The consumer, however, regrets the pigs of yesteryear or the poultry bred on farmyard that had tastier meat. At the same time, however, they request meat with a low fat content, which is paradoxical.

N-Alkane content of intramuscular lipids of Iberian fresh ham from different feeding systems and crossbreeding

n-Alkane content of intramuscular lipids ( Biceps femoris muscle) of the Iberian pig have been determined. Thirty-four pigs, divided into four groups, based in the feeding system ( Montanera, fed on acorns and pasture; and Pienso, fed on a concentrate feed) and in the genotype (Iberian pure pigs; and Iberian crossbred with Duroc 50%) were studied. n-Alkane content of intramuscular lipids has not been affected by neither crossbreeding nor feeding, although the analysis of feeds administered to the pigs showed greater n-alkane values in pasture (consumed by animals in montanera), than in acorns and concentrate feed.

Palmitic acid uptake by the rat soleus muscle in vitro

The rate of fatty acid uptake, oxidation, and deposition in skeletal muscles in relation to total and unbound to albumin fatty acids concentration in the medium were investigated in the incubated rat soleus muscle. An immunohistochemical technique was applied to demonstrate whether the albumin-bound fatty acid complex from the medium penetrates well within all areas of the muscle strips. It was found that the percentage of incorporation of palmitic acid into intramuscular lipids was fairly constant, independently of the fatty acid concentration in the medium, and amounted to 63–72% for triacylglycerols, 7–12% for diacylglycerols-monoacylglycerols, and 19–26% for phospholipids. Both palmitic acid incorporation into the muscle triacylglycerol stores and its oxidation to CO2 closely correlated with an increase in both total and unbound to albumin fatty acid concentrations in the incubation medium. Under conditions of increased total but constant unbound to albumin palmitic acid concentrations, the incorporation of palmitic acid into triacylglycerols and its oxidation to CO2 were also increased, but to a lower extent. This supports the hypothesis that the cellular fatty acid metabolism depends not only on the availability of fatty acids unbound to albumin, but also on the availability of fatty acids complexed to albumin.Key words: skeletal muscle, fatty acids, triacylglycerols, phospholipids.

Effects of Restricted Concentrate Feeding during the Early Growing Phase on Growth Performance, Carcass Characteristics and the Somatotropic Axis in Holstein Steers

Effects of nutritional restriction during the early growing phase on growth performance, carcass traits and the state of the somatotropic axis were investigated in 12 Holstein steers. During a rearing period (5 to 8 months old), 6 steers were given ad libitum access to a concentrate and a grass hay (ADLIB). The 6 other steers had their concentrate intake restricted at a rate of 1.5% of body weight (REST). Then, the steers of both groups were fattened with ad libitum access to another concentrate and the hay until slaughter (18 months old). The average daily gain for REST steers decreased (P<0.01) in the rearing period compared with ADLIB steers, whereas the difference tended to be reversed (P=0.10) in the fattening period. Feed conversion during fattening phase was improved (P<0.01) by the early nutritional restriction. Finishing weight, carcass weight, carcass grading factors and intramuscular lipid content were similar for both groups, but a trend for a higher (P=0.09) dressing percentage in the REST group was observed. Fat proportion in the 7th rib portionwas decreased (P<0.05) and the lean proportion tended to be increased (P=0.06) by restricted feeding. Restricted concentrate feeding decreased (P<0.05) plasma insulin-like growth factor I (IGF-I) at the end of the rearing period. The growth hormone (GH) secretory response to thyrotropin releasing hormone challenge and cellular density of pituitary GH cells, however, were unaffected by treatments. The results suggest that early nutritional restriction affect finishing carcass composition and the modulation of the developmental changes in plasma IGF-I may be involved in the process.

Carcass traits and microsatellite distributions in offspring of sires from three geographical regions of Japan.

We proposed that cattle sired by bulls from distinct geographical regions of Japan would differ in their ability to accumulate marbling and that they could be distinguished by differences in microsatellite genotypes. Semen was obtained from six, three, and one sire from the Hyogo, Shimane, and Tottori regions, respectively. Cows and heifers (n = 92) were bred by artificial insemination and raised at the Kyoto University Livestock Research Farm over several generations. The calves (n = 145) were 252 +/- 0.2 d of age (mean +/-SEM) and weighed 164 to 307 kg at the beginning of the finishing phase. Cattle produced from sires from the three regions differed significantly in days on feed (all significant differences P < 0.05). Carcass data were collected from 48, 36, and 19 offspring from the Hyogo, Shimane, and Tottori sires, respectively. There was no difference in slaughter weight (550 +/- 15 kg). Carcasses from Shimane progeny had more muscle than Hyogo cattle. Hyogo and Shimane cattle contained more kidney and 12th-rib fat than Tottori cattle, whereas Hyogo offspring had more 6th-rib fat than Shimane or Tottori offspring. There were no differences across regions in the monounsaturated:saturated fatty acid ratio. The rate of gain of 6th-rib fat for Hyogo progeny (0.033%/d) was significantly greater than that for Shimane or Tattori progeny (both 0.023%/d). Hyogo 12th-rib fat gain was 0.026%/d, which was significantly greater than that for Tottori progeny (0.010%/d). Shimane 12th-rib fat gain was intermediate (0.016%/d) between the other groups. Blood and muscle samples were used for the collection of DNA from 58, 30, and 18 offspring from the Hyogo, Shimane, and Tottori sires, respectively. Samples of the DNA were analyzed for 11 microsatellites. The BM1824 microsatellites for the Tottori progeny were not in Hardy-Weinberg equilibrium because of successive use of Hyogo sires on previous generations. The TGLA227 microsatellites for the Shimane cattle were not in Hardy-Weinberg equilibrium because of selective removal of progeny for slaughter. There were significant differences in allelic frequencies for the BM1824, ETH10, INRA23, and SPS115 and TGLA53 alleles across regions. These data are consistent with the geographical isolation of the different lines of Japanese Black cattle during their development and indicate the superiority of certain groups of sires in the accumulation of intramuscular lipid.

Early and long-term changes of equine skeletal muscle in response to endurance training and detraining.

Twenty-four 4-year-old Andalusian (Spanish breed) stallions were used to examine the plasticity of myosin heavy chain (MHC) phenotype and the metabolic profile in horse skeletal muscle with long-term endurance-exercise training and detraining. Sixteen horses underwent a training programme based on aerobic exercises for 8 months. Afterwards, they were kept in paddocks for 3 months. The remaining eight horses were used as controls. Three gluteus medius muscle biopsy samples were removed at depths of 20, 40 and 60 mm from each horse before (month 0), during (month 3) and after (month 8) training, and again after 3 months of detraining (month 11). MHC composition was analysed by electrophoresis and immunohistochemistry with anti-MHC monoclonal antibodies. Fibre areas, oxidative capacity and capillaries were studied histochemically. The activities of key muscle enzymes of aerobic (citrate synthase and 3-hydroxy-acyl-CoA-dehydrogenase) and anaerobic (phosphofructokinase and lactic dehydrogenase) metabolism and the intramuscular glycogen and triglyceride contents were also biochemically analysed. Early changes with training (3 months) included hypertrophy of type IIA fibres, a reduction of MHC-IIX with a concomitant increase of MHC-IIA, a rise in the number of high-oxidative fibres and in the activities of aerobic muscle enzymes and glycogen content. Long-term changes with training (8 months) were a further decline in the expression of MHC-IIX, an increase of slow MHC-I, additional increases of high-oxidative fibres, capillary density, activities of aerobic enzymes and endogenous glycogen; intramuscular lipid deposits also increased after 8 months of training whereas the activities of anaerobic enzymes declined. Most of exercise-induced alterations reverted after 3 months of detraining. These results indicate that endurance-exercise training induces a reversible transition of MHC composition in equine muscle in the order IIX-->IIA-->I, which is coordinated with changes in the metabolic properties of the muscle. Furthermore, a dose-response relationship was evident between the duration (in total) of training and the magnitude of muscle adaptations.

Acyl-CoA inhibition of hexokinase in rat and human skeletal muscle is a potential mechanism of lipid-induced insulin resistance.

There are strong correlations between impaired insulin-stimulated glucose metabolism and increased intramuscular lipid pools; however, the mechanism by which lipids interact with glucose metabolism is not completely understood. Long-chain acyl CoAs have been reported to allosterically inhibit liver glucokinase (hexokinase IV). The aim of the present study was to determine whether long-chain acyl CoAs inhibit hexokinase in rat and human skeletal muscle. At subsaturating glucose concentrations, 10 micromol/l of the three major long-chain acyl-CoA species in skeletal muscle, palmitoyl CoA (16:0), oleoyl CoA (18:1, n = 9), and linoleoyl CoA (18:2, n = 6), reduced hexokinase activity of rat skeletal muscle to 61 +/- 3, 66 +/- 7, and 57 +/- 5% of control activity (P < 0.005), respectively. The inhibition was concentration-dependent (P < 0.005) with 5 pmol/l producing near maximal inhibition. Human skeletal muscle hexokinase was also inhibited by long-chain acyl CoAs (5 pmol/l palmitoyl CoA decreased activity to 75 +/- 6% of control activity, P < 0.005). Inhibition of hexokinase in rat and human muscle by long-chain acyl CoAs was additive to the inhibition of hexokinase by glucose-6-phosphate (an allosteric inhibitor of hexokinase). This inhibition of skeletal muscle hexokinase by long-chain acyl CoA suggests that increases in intramuscular lipid metabolites could interact directly with insulin-mediated glucose metabolism in vivo by decreasing the rate of glucose phosphorylation and decreasing glucose-6-phosphate concentrations.

Changes in Fatty Acid Composition in Beef in Italy

Results from a study conducted in Italy concerning the updating of composition data of beef consumed in Italy are reported here. The study required a very wide sampling plan with regard to both animals and cuts to analyse. Data related to lipid composition of the most widely used type of beef consumed in Italy (young bull, 16–22 months old) show a reduction in total lipid content (which, according to the cuts, ranges between 1.8 and 10.2%) and a substantial change in fatty acid composition, with a high % of polyunsaturated fatty acids (mean 20% of total fatty acids). Such data have been confirmed by other studies conducted in Italy, and are in contrast with data reported in the tables of food composition from other countries, reporting a fatty acid composition characterized by a high fatty acid saturation degree. The occurrence of long-chain polyunsaturated fatty acid is probably due to the high ratio of phospholipids: triglycerides, occurring when the content in intramuscular lipid is very low; to the young age of animals; to the reduced activity of the rumen, where saturation of fatty acids occurs. It may be concluded that a fatty acid composition, which is particularly rich in polyunsaturated fatty acids, seems typical for Italian products.

Comparison of different magnesium sources on lamb muscle quality

Wether lambs ( n=20) were used to compare the effect of dietary magnesium oxide (MgO), unweathered Magnesium Mica® (UMM) and weathered Magnesium Mica® (WMM) on muscle quality. Lambs were fed a corn-based, control diet (Ctrl), or the Ctrl supplemented with either MgO, UMM, or WMM for 95 days before harvest. Following a 24-h chill, carcasses were fabricated, and L*, a* and b* values were determined on the triceps brachii (TB), longissimus thoracis (LT), semimembranosus (SM), and semitendinosus (ST) muscles. Supplemental magnesium had no ( P > 0.10) effect on live and carcass weights, fat thickness, loin eye area, and USDA yield grade. Carcasses from lambs supplemented with MgO had higher ( P < 0.10) flank streaking scores and USDA quality grades than those from lambs fed diets containing UMM. Although magnesium-supplementation had no ( P > 0.10) effect on marbling scores, the LT from Ctrl-fed lambs had more ( P < 0.05) intramuscular lipid than lambs fed diets containing UMM or WMM. Lambs supplemented with UMM had greater ( P < 0.05) LT shear force values than lambs fed MgO or WMM. Magnesium-supplementation had no ( P > 0.10) effect on muscle color; however, supplementing finishing diets with UMM may result in less palatable lamb.

Suicidal ideation among outpatients at general neurology clinics: prospective study

<h3>Abstract</h3> Specialized pro-resolving mediators (SPMs) actively limit inflammation and expedite its resolution. Here we profiled intramuscular lipid mediators following injury and investigated the role of SPMs in skeletal muscle inflammation...

Intramuscular lipid content is increased in obesity and decreased by weight loss

The triglyceride content of skeletal muscle samples determined by lipid extraction correlates with the severity of insulin-resistant glucose metabolism in muscle. To determine whether this reflects increased triglyceride within muscle fibers and to test the hypothesis that the lipid content in muscle fibers is increased in obesity, the present study was undertaken using quantitative histochemistry of Oil Red O staining of vastus lateralis muscle. A percutaneous muscle biopsy was performed in 9 lean subjects, 15 obese subjects without type 2 diabetes mellitus (DM), and 10 obese subjects with type 2 DM (body mass index [BMI], 23.4+/-1.0, 33.6+/-0.6, and 36.0+/-1.1 kg x m(-2) for lean, obese, and DM, respectively). Eight obese and 7 DM subjects had a weight loss and reassessment of muscle lipid content. Transverse muscle cryosections were examined by light microscopy with quantitative image analysis (grayscale images obtained by analog to digital conversion) to determine a lipid accumulation index (LAI) based on the percentage of cross-sectional fiber area occupied by lipid droplets. Muscle fiber lipid content was greater in obese individuals with DM than in lean individuals (3.62%+/-0.65% v 1.42%+/-0.28%, P < .05) but was not different in obese individuals without DM (2.53%+/-0.41%). Weight loss reduced the LAI from 3.43%+/-0.53% to 2.35%+/-0.31%. In summary, lipid accumulation within muscle fibers is significantly increased in obesity and is reduced by weight loss. This provides important information regarding the accumulation and distribution of skeletal muscle triglyceride in type 2 DM and obesity.

Restricted Feed Intake during Fattening Reduces Intramuscular Lipid Deposition without Modifying Muscle Fiber Characteristics in Rabbits

The present study was conducted to determine the effects of feed restriction during fattening on muscle fiber characteristics and intramuscular lipid traits. From 11 wk of age onward, rabbits were given free access to feed (control group), or received 70% of the control feed intake (restricted group). At the same weight at slaughter, restricted-fed rabbits were 3 wk older than controls (18 vs. 15 wk). The longissimus lumborum (LL, white loin), biceps femoris (BF, white thigh) and semimembranosus proprius (SMP, red thigh) muscles were then removed, and biochemical and histochemical assays were performed. In the three muscles, there was no effect of feed restriction on mean fiber size or percentage of the different fiber types. Restricted vs. control feeding resulted in a significant reduction (P<0.001) in total lipid content in all three muscles. This reduction was paralleled by a decline (P<0.001) in the activities of the malic enzyme and glucose-6 phosphate dehydrogenase (G6PDH), generating NADPH for the support of fatty acid synthesis. The diet-induced variations in lipid concentration and enzyme activities were larger (P<0.05) in the pure oxidative SMP muscle than in the predominantly fast-twitch glycolytic LL and BF muscles. Whatever feeding status, the ratio of malic enzyme to G6PDH activities was sharply lower (P<0.001) in SMP than in BF and LL muscles (averaging 1.5 vs. 9 and 15, respectively). These data indicate that nutritional status regulates intramuscular lipid deposition, without changing fiber-type composition. Further studies are necessary to determine the role of G6PDH in the lipogenic process of oxidative vs. glycolytic muscles.

Effect of free-range rearing and α-tocopherol and copper supplementation on fatty acid profiles and susceptibility to lipid oxidation of fresh meat from Iberian pigs

The effects of the feeding system (free-range versus confinement) and the inclusion in concentrate feeds of α-tocopheryl acetate (α-TAc) (0.100 g kg −1) and copper (II) sulphate (0.125 g kg −1) or both on meat oxidative susceptibility, α-tocopherol, intramuscular lipid fraction fatty acid and volatile aldehyde contents were determined in Biceps femoris muscle from Iberian pigs. m. Biceps femoris from free-range-reared Iberian pigs showed a significantly higher oleic acid percentage in neutral lipids ( p<0.001) than muscles from pigs fed in confinement, whereas confinement-pig muscles yielded higher arachidonic acid percentage ( p<0.05) in intramuscular fat and linoleic acid percentage ( p<0.05) in polar lipids. Copper (II) sulphate supplementation did not show any significant effect on fatty acid composition of lipid fractions of the B. femoris muscle. α-TAc supplementation highly increased the α-tocopherol content of muscles ( p<0.01). Free-range-reared pigs had the highest muscle FF61-tocopherol concentrations ( p<0.001), reflecting the high content found in the pasture. Both free-range rearing and α-TAc supplementation reduced susceptibility to iron-ascorbate-induced peroxidation and reduced hexanal content ( p<0.001). A clear relationship between the susceptibility to iron-ascorbate-induced peroxidation and the ratio between the concentration of polyunsaturated fatty acids in polar lipids and α-tocopherol content was found. The present results suggest a beneficial effect on meat quality when rearing hogs outdoors. They further suggest potential benefits to dry-cured products elaborated from free-range pigs as a result of a lower lipid oxidative trend of the meat.

Dietary tea reduces the iron content of beef

We hypothesized that the lightness of Japanese beef was related to the concentration of heme iron. In Experiment 1, six Japanese Black heifers were allotted randomly to one of three treatment groups: a basal concentrate ration (40% flaked corn) or the same diet and either 2 kg/d wheat bran or 0.5 kg/d green tea. After feeding the diets for 174 d, the cattle were slaughtered and the M. longissimus thoracis, M. semimembranosus, and M. gluteus medius were sampled for meat color, iron, and lipid content. The iron content of the M. semimembranosus from the tea-fed cattle was lower than in M. semimembranosus from the control cattle, and a∗ (redness) and √(a ∗2+b ∗2) (saturation) values were lower in M. semimembranosus from bran- and tea-fed cattle than in control cattle. Treatment main effects (across muscles) indicated that inclusion of tea in the diet increased intramuscular lipid and reduced the muscle iron content. There was a significant negative correlation ( r 2=0.79) between muscle iron content and L ∗ value (lightness). For Experiment 2, the effect of beef breed type on meat color and iron content of M. longissimus thoracis was investigated using stored meat samples from six breeds from a previous fattening experiment done under a high nutritional plane. Muscle iron content was significantly lower in Japanese Black cattle than in Japanese Black × Holstein or Japanese Black × Japanese Black/Holstein. There was no relationship between muscle iron content and intramuscular lipid content ( r 2=0.001). In Experiment 3, samples of M. longissimus dorsi were obtained from 17 Wagyu crossbred and 3 Angus crossbred cattle fed a corn concentrate diet in the USA for 148 d. Iron content of the M. longissimus thoracis from Japanese Black and Japanese Brown × Holstein cattle fattened in Japan was significantly less than the iron content of M. longissimus dorsi from cattle raised in the USA. Overall, the data indicate that it is possible to lower muscle iron, and lighten muscle color, by feeding green tea to Japanese cattle; also, there may be a genetic basis for the lower iron, and lighter color, of beef produced in Japan.

Intramuscular fatty acid composition of neutral and polar lipids for heavy-weight Angus and Simmental steers finished on pasture or grain

Samples of M longissimus thoracis et lumborum from 78 heavy steers (41 Angus, 37 Simmental) finished on three feed types (26 on annual pasture, 25 on perennial pasture, 27 on 70% grain) were analysed for fatty acid composition of triacylglycerols and polar lipids. High levels and a wide range of intramuscular lipid (105.8 g kg−1, SD = 34.8) were due to the very high mean carcass weight of 504.5 kg. Intramuscular lipid levels did not differ significantly between breeds or feed types. Significant differences between breeds and feed types were shown for most of the fatty acids measured in both triacylglycerols and polar lipids, with significant interactions for five polar lipid fatty acids. Levels of triacylglycerols and polar lipids were not affected by feed or breed. In addition to higher levels of 18:3, lipid from pasture groups also had higher levels of other n-3 acids including 20:5 and 22:5. Differences between the pasture groups were also found, but these were smaller than the differences between pasture-and grain-fed cattle. For several fatty acids, and particularly those in polar lipids, levels varied with overall lipid level. These results with very heavy cattle and a wide range of intramuscular fat levels show clearly that variability in intramuscular fatty acid composition may arise from differences in breed of cattle, feed type or lipid level in the muscle. © 1999 Society of Chemical Industry

This Month in the Journal

This Month in the Journal

Effect of fatty acid saturation in broiler diets on abdominal fat and breast muscle fatty acid composition and susceptibility to lipid oxidation

A total of 600 1-d-old Hybro N broiler chicks were randomly distributed into 24 litter pens and fed from 21 to 52 d of age isocaloric and isonitrogenous diets containing 8% of three different fat sources (tallow, lard or sunflower oil). Dietary treatment produced a significant effect (P < 0.05) in fatty acid composition of the intramuscular neutral lipids among all dietary treatments and for all lipid classes. A similar range of variation was obtained for abdominal fat fatty acid composition. In the intramuscular polar lipid fraction, dietary fat led to a narrow range in the variation of poly- and monounsaturated fatty acid composition, while the concentration of saturated fatty acids was maintained constant in all groups. A wide range in the melting point temperature of abdominal fat was observed (mean values of dietary treatments from 8.49 to 30.91 C), which indicates a major effect of dietary fatty acids on fat consistency. The variation of breast meat oxidation was small (mean values from 7.68 to 9.76 nmol malonaldehyde/mg protein). A dietary fat source rich in linoleic acid produces a marked effect on fat consistency, but only a moderately higher susceptibility to lipid oxidation of meat compared to tallow or lard.

Higher lipid accumulation in broilers fed on saturated fats than in those fed on unsaturated fats

1. Two experiments were conducted to assess the effect of fat sources differing in degree of saturation on the performance of and fat deposition in broiler chickens fed on isocaloric and isonitrogenous diets. 2. There were no differences in initial body weight between sexes but female broilers had lower daily gains (P <0.0001), final weights (P <0.0001) and food intakes (P <0.0001) than males. Abdominal fat pad weight was lower in male broilers than in female (P <0.001). 3. There were no significant differences in intake, weight gain, final body weight or food-to-gain ratios between birds fed on diets differing solely in the degree of fat saturation. Broilers fed on diets containing an animal fat blend or tallow had higher abdominal fat pad weight (P <0.001) and intramuscular lipid content (P =0.0085) than those fed on diets containing sunflower oil. 4. It was concluded that dietary fat saturation affects fat accumulation in broiler chickens.